Percussion device



Jan. 20, 1942.

W. M. DRENNON PERCUSSION DEVICE Filed Sept. 11, 1939 2 Sheets-Sheet l (5,, J .ra'gg 1 a Jan. 20, 1942.

w. DRENN ON PERCUSSION DEVICE Filed Sept. 11, 1959 2 Sheets-Sheet 2 '4 I villi/1111111! 7 Int/en i'or. Mlliam M fire/"zonthe pump. "ne'cted to the drive shaft continually rotate the 55 receive the end of a flexible shaft 80 whichleads Patented Jan. 20, 1942 PERCUSSION DEVICE William M. Drennon, Anaheim, Calif assignor of one-third to Collins Mason, Beverly Hills,

Calif.

Application September 11, 1939, Serial No. 294,239

6 Claims.

My invention has to do with percussion devices and, in its more particular aspects, relates to pneumatic hammers of the class wherein a reciprocatory plunger element is brought into forceable impact against a drill or the like.

An object of the invention resides in the provision of a device of this class in which the hammer plunger is raised by mechanical means and the impacting blow is caused by fluid under pressure.

Another object is the elimination of all possible springs inasmuch as springs in a tool of this type rapidly deteriorate and crystallize and require frequent renewal.

Another object is the provision in such a device of means for rotating the percussion tool during operation.

Another object is to provide in such a device means connected with the mechanical element employed to raise the hammer plunger, for delivering fluid under pressure to a pressure chamber.

Another object is to provide a pneumatic percussion device which requires a minimum of fluid for its operation.

Another object is to provide a durable, simple and efficient percussion device which may be portable, compact and economical of manufacture.

Other objects and corresponding attainments of my invention will become obvious to those skilled in the art from the particular adaptation thereof which I illustrate in the accompanying drawings and describe hereinafter.

In the drawings:

Fig. 1 is a vertical section of my device, with some parts being shown in elevation;

Fig. 2 is a section on line -2--2 of Fig. 1;

Fig. 3 is a section on line 3-3 of Fig. 1;

Fig. 4 is a section on line 4-4 of Fig. 1; and

Fig. 5 is a sectional view similar to Fig. 2 but showing the hammer plunger in its lower extreme position.

In general, I carry my invention into practice by providing a hammer which is in the form of pression by a pump, which pressure imparts the striking force to the plunger. The hammer is raised after each stroke by means of a cam rotated by a drive shaft connected to a suitable power means, said drive shaft also operating A train of gears operatively conpercussion tool being impacted by the hammer,

such tool being slidably mounted in an axial opening in one of the gears of said train.

Referring now to the drawings, I show a body 5 having bottom end plate 6 secured to it by screws 1, a side plate 8 secured by screws 9, an opposite side plate l0 secured by screws II and a top cover plate |2 secured by screws l3, said top plate covering a recess formed in the top of the body to provide a fluid pressure chamber IS. A top handle I6 is preferably formed integral with plate I2 and a side handle I1 is secured to the body by screws H3.

The body is provided with a longitudinal bore in which is slidably mounted a hammer plunger 2|, the top of which communicates with chamber l5 and is provided with a cup washer 24 secured to its end by screw 25, and which plunger is slidably carried at its end in bushing 26, which bushing is threadedly mounted in the enlarged top end of bore 20 and has tool receiv ing slots 26a to facilitate its removal. Plunger 2| is round in cross section except for that portion 30 intermediate its end, which is flattened to provide opposite shoulders 3|, 32. The lower end of hammer 2| is provided with a longitudinal bore within which is slidably mounted the anvil member 36, which anvil is provided with a head 31. The lower end of the hammer is slidably mounted in bushings 40, 4| and packing gland 42. e

The bottom end of the body is provided with a recess within which the tool holding end rotating assembly to be later described is housed, said recess being covered by end plate 6.

Extending transversely of the body and journalled in ball bearings 50, 5| and 52 is a drive shaft 55. Secured to the drive shaft within body recess 60, which recess is closed by screwthreaded plug 6|, there is a bevel gear 62. Secured to one end of shaft 55, I provide cams 64, 65, which rotate on opposite sides of the flattened portion 30 of the hammer plunger and are adapted to engage the cam surfaces provided by key member 61, which key is force-fitted into a transverse hole 61a in the plunger, the upper curved portion of the key fitting into socket portions 68 provided in the shoulder 3| of the plunger, and thekey being secured in position by a pin 69. A power transmitting shaft 10 is journalled in bearings 12 and I3 and carries pinion gear 14 which meshes with larger gear I5 secured to drive shaft 55, the outer end of shaft 10 having annular flange I1 and being socketed at 18 to to a suitable power means, not shown, such as an electric motor. Shaft I is held against longitudinal movement in its bearings by flanged sleeve 82 which is threadedly mounted on the threaded portion 83 of end plate I0.

Operatively connected to the inner end of drive shaft 55, by crank 9| and connecting rod 90, there is a pump plunger 92 which is slidably mounted in a cylinder bore 95 provided in the body. At the top end of the bore 95 there is a plug I00 which has a central bore IOI in which is mounted a spring pressed ball valve I02, whose spring I03 seats at its lower end against ball I02 and at its top end against screwthreaded plug I04. Mounted in the bore of a plug IIO, which forms a closure for opening I09 extending from chamber I to atmosphere, there is a spring pressed ball safety valve I I I whose spring is held against the valve by plug H2 which has an outlet port I I5 communicating to atmosphere.

Journalled in ball bearing I20, in end plate 6, there is a percussion tool holding sleeve I2I which carries an integral gear I22 and which has a bore of square cross-section to receive the similarly shaped end of a tool T, such as a drill or the like. A packing washer I25 surrounds the lower end of sleeve I2I and is held against longitudinal ball bearings I45 and I46 and carries gear I43 at its upper end and pinion M! at its lower end. Pinion I40 is secured on a spindle I48 which is journalled at one end in ball bearing I50 and at its other end in ball bearing I5 I.

A manually operated control lever I60 is journalled in body projection I6I. A lever I60a is secured to the end of the control lever by a pin I62 and its lower bifurcated end straddles the flattened portion of stem I64 and is adapted to engage the shoulder I63 on stem I64. Stem I64 is slidably mounted through threaded plug I65, the

inner end of which plug compresses a coil spring I66 against the inner annularly flanged portion I61 of stem I64 and the inner end portion I68 of the stem is adapted to fit into recess I69 in the side wall of the hammer when stem I64 is pushed inwardly against the pressure of spring N66, to halt sliding movement of the plunger, it being shown in such position in Fig. 2. In that position, the cams 64 and 65 will clear key 61 so that further rotation of the cams will not have any lifting effect on the plunger until the stem I64 is again moved outwardly from engagement with the recess by means of its spring I66.

In operation, the power to raise the hammer plunger, to operate the pump and to rotate the percussion tool, is transmitted by means of flexible shaft 80 which is operatively connected through pinion I4 and gear I5 to shaft 55. Upon rotation in a counter-clockwise direction, the cams 64 and 65 gradually engage keys 6'! to raise the hammer plunger from the position of Fig. 5 to the position of Fig. 2, at which point the cams are suddenly disengaged from the keys to allow the fluid pressure within chamber I5 to force the plunger downward causing the plunger to strike the anvil 36, which in turn acts against the upper end of the tool T. While shaft 55 is rotated to so rotate the cams, it is also, by virtue of crank BI and connecting rod 90, operating the pump to maintain the fluid in chamber I5 under suitable compression, and, through gear I43, shaft I42, pinions I4I, I40 and gear I22, continually rotating the tool T. In case the pressure within chamber I5 becomes excessive, it is automatically relieved by the pop-off valve III, which may be adjusted by screwing plug H2 in or out to vary the compression on the valve spring. The device is extremely easy to assemble and cover plates 6, 8, I0, I2 and plug 6| make all the parts easily accessible.

My invention may be embodied in other specific forms without departing from the spirit or essential characteristics thereof. The present embodiment is therefore to be considered in all respects as illustrative and not restrictive, the scope of the invention being defined by the appended claims rather than by the foregoing description, and all changes which come within the meaning and range of equivalency are therefore intended to be embraced therein.

I claim:

1. A percussion device including a body having a cylinder bore therein and a fluid pressure chambier communicating with the bore, a piston slidably mounted in the bore, a drive shaft in the body, cam means on the shaft, said cam means cooperating with the piston to raise the same in the cylinder and disengage therefrom at a predetermined point in its travel to permit the fluid pressure within the chamber to force the piston downwardly, an anvil member engageable by the lower end of the piston, a rotatable member journalled in the body for slidably supporting a percussion tool, means operably connecting said rotatable member with said drive shaft whereby rotation of the drive shaft imparts rotation to the said rotatable member, a pump cylinder bore in the body, a pump plunger slidably mounted in the said latter bore, reciprocating means connected at one end to the drive shaft and at its other end to the pump plunger, a valve in the pump cylinder bore between the pump plunger and the fluid pressure chamber, said valve being operable by the up-stroke of the pump plunger to permit fluid to pass from the pump cylinder bore into the chamber, spring means automatically closing said valve as the pump plunger begins its downward stroke, and a fluid inlet port communicating with the pump cylinder bore at a point above the upper end of the pump plunger when said plunger is in its lowermost position in the cylinder bore.

2. A percussion device including a body having a cylinder bore therein and a fluid pressure chamber communicating with the bore, a piston slidably mounted in the bore, a drive shaft in the body, cam means on the shaft, said cam means cooperating with the piston to raise the same in the cylinder and disengage therefrom at a predetermined point in its travel to permit the fluid pressure within the chamber to force the piston downwardly, an anvil member engageable by the lower end of the piston, a rotatable member journalled in the body for slidably supporting a percussion tool, means operably connecting said rotatable member with said drive shaft whereby rotation of the drive shaft imparts rotation to the said rotatable member, apump cylinder bore in the body, a pump plunger slidably mounted in the said latter bore, reciprocating means connected at one end to the drive shaft and at its other end to the pump plunger, a valve in the pump cylinder bore between the pump plunger and the fluid pressure chamber, said valve being operable by the up-stroke of the pump plunger to permit fluid to pass from the pump cylinder bore into the chamber, spring means automatically closing said valve as the pump plunger begins its downward stroke, a fluid inlet port communicating with the pump cylinder bore at a point above the upper end of the pump plunger when said plunger is in its lowermost position in the cylinder bore, and a pressure relief valve in the body communicating from the chamber to atmosphere, said pressure relief valve being operable by fluid pressure within the chamber.

3. A percussion device comprising a body having a longitudinal cylinder bore therein, said bore having wall portions providing a fluid pressure chamber at the top end thereof, with which chamber the top end of the cylinder bore communicates, a hammer plunger mounted to reciprocate in said bore and forming a fluid tight closure for said bore at its point of communication with the chamber, a drive shaft journalled in and disposed transversely of the body, cam means on the drive shaft, said cam means cooperating with the hammer plunger to raise the same in the bore against the fluid pressure within the chamber, a pump in the body for maintaining fluid under pressure within the chamber, said pump being independent of the hammer plunger, and means operatively connecting said pump to the drive shaft whereby the pump is operated upon rotation of the drive shaft.

4. A percussion device comprising a body having a cylinder bore and walls defining a fluid pressure chamber in communication with said bore, a hammer plunger mounted to reciprocate in the bore, a continuously rotatable drive shaft journalled in the body, cam means on the drive shaft and cooperating with the hummer plunger to engage and raise the same, said hammer plunger being given its downward movement in the bore by virtue of the fluid pressure in said chamber, a pump communicating with the chamber to continuously charge the same with fluid under pressure, means operatively connecting the pump to the drive shaft whereby to operate the pump continuously, manually slidable control means mounted in the body for engagement with the hammer plunger when the hammer is in its raised position whereby to hold the hammer plunger against movement in the bore without interfering with operation of the drive shaft and pump, said last mentioned means comprising a pin slidably mounted in the body for engagement with the hammer plunger, spring means normally holding the pin out of engagement with the hammer,

' pressure within the chamber to force the piston downwardly, a pump cylinder bore in the body, a pump plunger slidably mounted in the said latter bore, reciprocating means connected at one end to the drive shaft and at its other end to the pump plunger, a valve in the pump cylinder bore between the pump plunger and the fluid pressure chamber, said valve being operable by the upstroke of the pump plunger to permit fluid to pass from the pump cylinder bore into the chamber, spring means automatically closing said valve as the pump plunger begins its downward stroke, and a fluid inlet port communicating with the pump cylinder bore at a point above the upper end of the pump plunger, when the plunger is in its lowermost position in the cylinder bore.

6. A percussion device comprising a body, a cylinder bore therein, a plunger reciprocally mounted in the bore, walls forming a fluid pressure chamber in the body, the upper end of said bore opening into and having unrestricted communication with the chamber whereby to continuously expose the upper end of the plunger to the fluid pressure in the chamber to urge it downwardly in the bore, mechanical means for moving the plunger upwardly in the bore against said fluid pressure, means for continuously creating operating fluid pressure in the chamber, and a pressure-actuated release Valve for releasing from the chamber any pressure in excess of a predetermined maximum operating pressure, said chamber being substantially closed against release of pressure therein so long as the pressure in the chamber does not exceed said maximum.

WILLIAM M. DRENNON. 

